Allow CVars to be registered late, improve usability for dynamically registered CVars.

Now we store the raw JSON value in memory for unregistered CVars.

Intended to be used for mod CVars, as we obviously can't statically define all of those.

CVar names are now stored as an std::string, so the lifetime is easy to manage when dynamically registered.

CVars cannot be moved/copied anymore. We had some code that was accidentally relying on this, and I fixed that.

include/dusk/config.hpp

@@ -89,17 +89,16 @@ public:
  */
 void Register(ConfigVarBase& configVar);
 
-/**
- * \brief Indicate that all registrations have happened and everything should lock in.
- */
-void FinishRegistration();
-
 /**
  * \brief Load config from the standard user preferences location.
  */
 void LoadFromUserPreferences();
 void LoadFromFileName(const char* path);
 
+void LoadArgOverride(std::string_view name, std::string_view value);
+
+void Shutdown();
+
 /**
  * \brief Save the config to file.
  */

include/dusk/config_var.hpp

@@ -68,7 +68,7 @@ protected:
     /**
      * The name of this CVar, used in the configuration file.
      */
-    const char* name;
+    std::string name;
 
     /**
      * Whether this CVar has been registered with the global managing logic.
@@ -86,8 +86,10 @@ protected:
      */
     const ConfigImplBase* impl;
 
-    ConfigVarBase(const char* name, const ConfigImplBase* impl);
-    virtual ~ConfigVarBase() = default;
+    // The configuration system stores a direct pointer to the ConfigVar instance.
+    // It is not legal to move or copy it.
+    ConfigVarBase(const ConfigVarBase&) = delete;
+    ConfigVarBase(std::string name, const ConfigImplBase* impl);
 
     /**
      * Check that the CVar is registered, aborting if this is not the case.
@@ -98,6 +100,8 @@ protected:
     }
 
 public:
+    virtual ~ConfigVarBase();
+
     /**
      * Get the name of this CVar, used in the configuration file.
      */
@@ -120,6 +124,7 @@ public:
      * This is necessary to make it legal to access.
      */
     void markRegistered();
+    void unmarkRegistered();
 
     /**
      * Clear a speedrun-mode override if one is active on this CVar.
@@ -185,10 +190,12 @@ public:
      * @param arg Arguments to forward to construct the default value.
      */
     template <typename... Args>
-    ConfigVar(const char* name, Args&&... arg)
-        : ConfigVarBase(name, GetConfigImpl<T>()), defaultValue(std::forward<Args>(arg)...),
+    ConfigVar(std::string name, Args&&... arg)
+        : ConfigVarBase(std::move(name), GetConfigImpl<T>()), defaultValue(std::forward<Args>(arg)...),
         value(), overrideValue() {}
 
+    ConfigVar(ConfigVar const&) = delete;
+
     /**
      * \brief Get the current value of the CVar.
      *